1. Field of the Invention
The present invention relates to equipment for semiconductor fabrication, and more particularly, to an air intake apparatus installed in chemical vapor deposition (CVD) equipment and method for removing ozone using the same.
2. Description of the Related Art
Fine particles or chemicals may contaminate a highly integrated semiconductor device during fabrication, thereby lowering the quality of the final product. In particular, when manufacturing a very large-scale integrated semiconductor device such as a 1 GB DRAM having a 0.18 .mu.m line width, fine particles or chemicals may unexpectedly disrupt the fabrication process. Thus, careful attention is required to suppress particulate contaminants, and conventional semiconductor fabricating equipment must be carefully examined if high quality very large-scale integrated semiconductor devices are to be produced successfully. Semiconductor fabricating equipment which execute processes that vary in response to environmental factors, such as air purity, must be especially considered.
Such semiconductor fabricating equipment generally uses various types of filters in order to filter out potential contaminants. However, most filters can remove only solid particles, i.e., particulate contaminants, and not chemical contaminants. As a result, ozone (O.sub.3), oxygen-nitrogen compounds (NO.sub.x), and oxygen-sulfur compounds (SO.sub.x) flow into semiconductor fabricating equipment via the filter, without being eliminated by the filter. The O.sub.3, NO.sub.x and SO.sub.x cause chemical reactions to occur in the wafer being processed. These chemical reactions lower the quality of the resultant semiconductor device.
Moreover, many types of semiconductor fabricating equipment are sensitive to chemical contaminants. In particular, such chemical contamination is especially serious in chemical vapor deposition (CVD) equipment used to carry out a hemispherical polysilicon grain process.
FIGS. 1 and 2 show conventional air intake apparatus of semiconductor fabricating equipment.
FIG. 1 shows an air intake apparatus which is mainly used when the air intake path is relatively short, and FIG. 2 shows an air intake apparatus which is mainly used when the air intake path is relatively long. The air intake apparatus includes a fan 10 for drawing air from the outside into the equipment, and a high efficiency particle air (HEPA) filter 12 for removing particulate contaminants entrained in the air. That is, after air is drawn in from the outside via the fan 10, the particulate contaminants in the air are eliminated using the HEPA filter 12. Reference numeral 14 in FIG. 1 designates a pre-filter for eliminating large particulate contaminants upstream of the fan 10.
However, since the above-described air intake apparatus for semiconductor fabricating equipment cannot remove chemical contaminants existing in the air, such as O.sub.3, NO.sub.x and SO.sub.x, the chemicals flow to the equipment, thereby adversely affecting the quality of the semiconductor device being manufactured. This problem is, again, particularly serious in CVD equipment used to form hemispherical polysilicon grains (HSGs).